Reorganize net/disk_cache into backend specific directories.

net/disk_cache/v3/backend_impl_v3.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// See net/disk_cache/disk_cache.h for the public interface of the cache.
-
-#ifndef NET_DISK_CACHE_V3_BACKEND_IMPL_V3_H_
-#define NET_DISK_CACHE_V3_BACKEND_IMPL_V3_H_
-
-#include "base/containers/hash_tables.h"
-#include "base/files/file_path.h"
-#include "base/timer/timer.h"
-#include "net/disk_cache/block_files.h"
-#include "net/disk_cache/disk_cache.h"
-#include "net/disk_cache/stats.h"
-#include "net/disk_cache/stress_support.h"
-#include "net/disk_cache/trace.h"
-#include "net/disk_cache/v3/block_bitmaps.h"
-#include "net/disk_cache/v3/eviction_v3.h"
-#include "net/disk_cache/v3/index_table.h"
-
-namespace net {
-class NetLog;
-}  // namespace net
-
-namespace disk_cache {
-
-class EntryImplV3;
-
-// This class implements the Backend interface. An object of this
-// class handles the operations of the cache for a particular profile.
-class NET_EXPORT_PRIVATE BackendImplV3 : public Backend {
- public:
-  enum BackendFlags {
-    MAX_SIZE = 1 << 1,            // A maximum size was provided.
-    UNIT_TEST_MODE = 1 << 2,      // We are modifying the behavior for testing.
-    UPGRADE_MODE = 1 << 3,        // This is the upgrade tool (dump).
-    EVICTION_V2 = 1 << 4,         // Use of new eviction was specified.
-    BASIC_UNIT_TEST = 1 << 5,     // Identifies almost all unit tests.
-    NO_LOAD_PROTECTION = 1 << 6,  // Don't act conservatively under load.
-    NO_BUFFERING = 1 << 7,        // Disable extended IO buffering.
-    NO_CLEAN_ON_EXIT = 1 << 8     // Avoid saving data at exit time.
-  };
-
-  BackendImplV3(const base::FilePath& path,
-                base::MessageLoopProxy* cache_thread,
-                net::NetLog* net_log);
-  virtual ~BackendImplV3();
-
-  // Performs general initialization for this current instance of the cache.
-  int Init(const CompletionCallback& callback);
-
-  // Same behavior as OpenNextEntry but walks the list from back to front.
-  int OpenPrevEntry(void** iter, Entry** prev_entry,
-                    const CompletionCallback& callback);
-
-  // Sets the maximum size for the total amount of data stored by this instance.
-  bool SetMaxSize(int max_bytes);
-
-  // Sets the cache type for this backend.
-  void SetType(net::CacheType type);
-
-  // Creates a new storage block of size block_count.
-  bool CreateBlock(FileType block_type, int block_count,
-                   Addr* block_address);
-
-  // Updates the ranking information for an entry.
-  void UpdateRank(EntryImplV3* entry, bool modified);
-
-  // Permanently deletes an entry, but still keeps track of it.
-  void InternalDoomEntry(EntryImplV3* entry);
-
-  // This method must be called when an entry is released for the last time, so
-  // the entry should not be used anymore. |address| is the cache address of the
-  // entry.
-  void OnEntryDestroyBegin(Addr address);
-
-  // This method must be called after all resources for an entry have been
-  // released.
-  void OnEntryDestroyEnd();
-
-  // If the |address| corresponds to an open entry, returns a pointer to that
-  // entry, otherwise returns NULL. Note that this method does not increase the
-  // ref counter for the entry.
-  EntryImplV3* GetOpenEntry(Addr address) const;
-
-  // Returns the id being used on this run of the cache.
-  int32 GetCurrentEntryId() const;
-
-  // Returns the maximum size for a file to reside on the cache.
-  int MaxFileSize() const;
-
-  // A user data block is being created, extended or truncated.
-  void ModifyStorageSize(int32 old_size, int32 new_size);
-
-  // Logs requests that are denied due to being too big.
-  void TooMuchStorageRequested(int32 size);
-
-  // Returns true if a temporary buffer is allowed to be extended.
-  bool IsAllocAllowed(int current_size, int new_size);
-
-  // Tracks the release of |size| bytes by an entry buffer.
-  void BufferDeleted(int size);
-
-  // Only intended for testing the two previous methods.
-  int GetTotalBuffersSize() const {
-    return buffer_bytes_;
-  }
-
-  // Returns true if this instance seems to be under heavy load.
-  bool IsLoaded() const;
-
-  // Returns the full histogram name, for the given base |name| and the current
-  // cache type. The name will be "DiskCache3.name_type".
-  std::string HistogramName(const char* name) const;
-
-  net::CacheType cache_type() const {
-    return cache_type_;
-  }
-
-  bool read_only() const {
-    return read_only_;
-  }
-
-  // Returns a weak pointer to this object.
-  base::WeakPtr<BackendImplV3> GetWeakPtr();
-
-  // Returns true if we should send histograms for this user again. The caller
-  // must call this function only once per run (because it returns always the
-  // same thing on a given run).
-  bool ShouldReportAgain();
-
-  // Reports some data when we filled up the cache.
-  void FirstEviction();
-
-  // Called when an interesting event should be logged (counted).
-  void OnEvent(Stats::Counters an_event);
-
-  // Keeps track of payload access (doesn't include metadata).
-  void OnRead(int bytes);
-  void OnWrite(int bytes);
-
-  // Timer callback to calculate usage statistics and perform backups.
-  void OnTimerTick();
-
-  // Sets internal parameters to enable unit testing mode.
-  void SetUnitTestMode();
-
-  // Sets internal parameters to enable upgrade mode (for internal tools).
-  void SetUpgradeMode();
-
-  // Sets the eviction algorithm to version 2.
-  void SetNewEviction();
-
-  // Sets an explicit set of BackendFlags.
-  void SetFlags(uint32 flags);
-
-  // Sends a dummy operation through the operation queue, for unit tests.
-  int FlushQueueForTest(const CompletionCallback& callback);
-
-  // Trims an entry (all if |empty| is true) from the list of deleted
-  // entries. This method should be called directly on the cache thread.
-  void TrimForTest(bool empty);
-
-  // Trims an entry (all if |empty| is true) from the list of deleted
-  // entries. This method should be called directly on the cache thread.
-  void TrimDeletedListForTest(bool empty);
-
-  // Performs a simple self-check, and returns the number of dirty items
-  // or an error code (negative value).
-  int SelfCheck();
-
-  // Backend implementation.
-  virtual net::CacheType GetCacheType() const OVERRIDE;
-  virtual int32 GetEntryCount() const OVERRIDE;
-  virtual int OpenEntry(const std::string& key, Entry** entry,
-                        const CompletionCallback& callback) OVERRIDE;
-  virtual int CreateEntry(const std::string& key, Entry** entry,
-                          const CompletionCallback& callback) OVERRIDE;
-  virtual int DoomEntry(const std::string& key,
-                        const CompletionCallback& callback) OVERRIDE;
-  virtual int DoomAllEntries(const CompletionCallback& callback) OVERRIDE;
-  virtual int DoomEntriesBetween(base::Time initial_time,
-                                 base::Time end_time,
-                                 const CompletionCallback& callback) OVERRIDE;
-  virtual int DoomEntriesSince(base::Time initial_time,
-                               const CompletionCallback& callback) OVERRIDE;
-  virtual int OpenNextEntry(void** iter, Entry** next_entry,
-                            const CompletionCallback& callback) OVERRIDE;
-  virtual void EndEnumeration(void** iter) OVERRIDE;
-  virtual void GetStats(StatsItems* stats) OVERRIDE;
-  virtual void OnExternalCacheHit(const std::string& key) OVERRIDE;
-
- private:
-  friend class EvictionV3;
-  typedef base::hash_map<CacheAddr, EntryImplV3*> EntriesMap;
-
-  void AdjustMaxCacheSize();
-  bool InitStats(void* stats_data);
-  void StoreStats();
-
-  // Deletes the cache and starts again.
-  void RestartCache(bool failure);
-  void PrepareForRestart();
-
-  // Performs final cleanup.
-  void CleanupCache();
-
-  // Creates a new entry object. Returns zero on success, or a disk_cache error
-  // on failure.
-  int NewEntry(Addr address, EntryImplV3** entry);
-
-  // Opens the next or previous entry on a cache iteration.
-  int OpenFollowingEntry(bool forward, void** iter, Entry** next_entry,
-                         const CompletionCallback& callback);
-
-  // Handles the used storage count.
-  void AddStorageSize(int32 bytes);
-  void SubstractStorageSize(int32 bytes);
-
-  // Update the number of referenced cache entries.
-  void IncreaseNumRefs();
-  void DecreaseNumRefs();
-  void IncreaseNumEntries();
-  void DecreaseNumEntries();
-
-  // Dumps current cache statistics to the log.
-  void LogStats();
-
-  // Send UMA stats.
-  void ReportStats();
-
-  // Reports an uncommon, recoverable error.
-  void ReportError(int error);
-
-  // Performs basic checks on the index file. Returns false on failure.
-  bool CheckIndex();
-
-  // Part of the self test. Returns the number or dirty entries, or an error.
-  int CheckAllEntries();
-
-  // Part of the self test. Returns false if the entry is corrupt.
-  bool CheckEntry(EntryImplV3* cache_entry);
-
-  // Returns the maximum total memory for the memory buffers.
-  int MaxBuffersSize();
-
-  IndexTable index_;
-  base::FilePath path_;  // Path to the folder used as backing storage.
-  BlockBitmaps block_files_;
-  int32 max_size_;  // Maximum data size for this instance.
-  EvictionV3 eviction_;  // Handler of the eviction algorithm.
-  EntriesMap open_entries_;
-  int num_refs_;  // Number of referenced cache entries.
-  int max_refs_;  // Max number of referenced cache entries.
-  int entry_count_;  // Number of entries accessed lately.
-  int byte_count_;  // Number of bytes read/written lately.
-  int buffer_bytes_;  // Total size of the temporary entries' buffers.
-  int up_ticks_;  // The number of timer ticks received (OnTimerTick).
-  net::CacheType cache_type_;
-  int uma_report_;  // Controls transmission of UMA data.
-  uint32 user_flags_;  // Flags set by the user.
-  bool init_;  // controls the initialization of the system.
-  bool restarted_;
-  bool read_only_;  // Prevents updates of the rankings data (used by tools).
-  bool disabled_;
-  bool lru_eviction_;  // What eviction algorithm should be used.
-  bool first_timer_;  // True if the timer has not been called.
-  bool user_load_;  // True if we see a high load coming from the caller.
-
-  net::NetLog* net_log_;
-
-  Stats stats_;  // Usage statistics.
-  scoped_ptr<base::RepeatingTimer<BackendImplV3> > timer_;  // Usage timer.
-  scoped_refptr<TraceObject> trace_object_;  // Initializes internal tracing.
-  base::WeakPtrFactory<BackendImplV3> ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(BackendImplV3);
-};
-
-}  // namespace disk_cache
-
-#endif  // NET_DISK_CACHE_V3_BACKEND_IMPL_V3_H_